Physical therapist examining a patient's knee on a treatment table

Deep Vein Thrombosis (DVT): Blood Clot in the Leg Explained

shutterstock_89651743http://www.dvtforum.com/index.asp?action=start A few days ago a patient came into the clinic with complaints of pain in the back of his knee after spending hours driving his car back to Washington from the east coast.  He didn’t recall injuring his leg or knee and told me that the pain was worse when he starts walking.  He also noted some swelling in the leg and ankle.  I became concerned about the possibility of a blood clot (also called a deep vein thrombosis or DVT) in his leg after hearing about his long journey because sitting for extended periods of time in a car or on an airplane are big risk factors for a deep vein thrombosis.  After the ultrasound confirmed a blood clot in his left leg, we started him on the treatment and he is doing great today. A blood clot (also called a thrombus) can be very serious and even life threatening if it breaks and travels through the circulatory system.  If that happens, the blot clot (now called an embolis to indicate that it broke off from the main clot and is traveling through the veins of the body) can lodge in the lung and cause a pulmonary embolism (PE) which is a serious condition that causes over 50,000 deaths a year in the U.S.A. A deep vein thrombosis (DVT) is a problem where a blood clot is created inappropriately within the vein.  Most commonly these veins are in the “deep veins” of the leg, pelvis, or thigh.  The thrombus can block or partially block the blood flowing through the vein and cause pain and swelling. Symptoms:  These may or may not all be present: 1)      Pain – usually in one leg, or knee 2)     Swelling in that leg or knee 3)     Warmth and redness in the leg or knee area Diagnosis:  If a medical provider suspects that you might have a DVT, there are certain tests that can be done to look for this including: 1)      Compression ultrasonography (ultrasound) which uses sound waves to allow the visualization of the blood flow through the veins of the leg. 2)     D-dimer is a blood test that is often elevated in people who have a blood clot.  It can also be elevated for other reasons, so an elevated D-dimer does not tell us that a patient has a blood clot, but if the D-dimer is not elevated and  the risk factors are low, there is less chance of the patient having a blood clot. 3)     MRI uses a very strong magnet to create photos inside the leg and is expensive so it’s not the first choice the diagnose blood clots. 4)     Contrast venography is when a small tube (called a catheter) is inserted into the vein and a liquid that shows up on x-ray (we call this contrast) is injected through the tube while xray is used to visualize the blood flow of the contrast through the vein.  We usually prefer to use ultrasound, but this test can be helpful when ultrasound is not available. Risk factors for DVT: 1)      Some people have a genetic problem called thrombophilia which causes blood to clot more easily than it should 2)     Cancer 3)     Smoking 4)     Heart failure 5)     Pregnancy 6)     Being overweight or obese 7)     Increased age 8)     Having had a DVT or PE in the past 9)     Certain kidney problems 10)  Medications such as birth control pills or hormone replacement therapy 11)  Recent surgery – especially involving the knee, hip or pelvis 12)  Trauma – such as a fall or deep bruise where the blood vessels may have become injured 13)  Sitting for long periods of time such on a long flight or a long drive in a vehicle.  We also think about this for elderly patients who don’t move around very much Treatment:  The goal in treating a DVT is to prevent the blood clot from dislodging or breaking off and becoming an embolism that could lodge into the lung (pulmonary embolism).  We also want to prevent the clot from getting larger or new clots from forming. Medications can be used to prevent new blood clots from forming(anticoagulants), and other medications can be used to dissolve a blood clot (thrombolytic).  Most people might think that the primary treatment would be to dissolve the clot using thrombolytic therapy, however this is usually not the case.  The body has natural substances to dissolve blood clots that are formed inappropriately in blood vessels and we usually prefer the body to do this naturally while assisting by giving medications to prevent new blood clots from forming.  Anticoagulant medications such as warfarin or heparin are the most common agents used to treat patients with DVTs at this time.  For patients who continually develop blood clots despite being on medications or who cannot take the recommended medications, a filter might be inserted into one of the largest veins in the body (the inferior vena cava) to block the circulation of blood clots.  We strategically place the filter so that if a blood clot forms, it is not allowed to reach the lungs. Prevention:  For patients at high risk of developing a blood clot such as a patient who just had surgery, or someone who has cancer, they might be started on anticoagulant medications to decrease the risk of a blood clot.  Some patients are fitted with inflatable compression devices that are worn on the legs and periodically fill with air and put compression on the legs and work similar to how an electronic blood pressure cuff inflates. If you or someone you know is having symptoms that you think might be related to a blood clot or DVT, I recommend that you have them evaluated immediately.   I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, D.O.
Board Certified in Obesity Medicine and Family Medicine

This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.

Clinician reviewing a chest CT scan on a computer monitor

Blood Clot in the Lung: What Is a Pulmonary Embolism?

shutterstock_94626226A patient who regularly competes in Iron Man Triathlons came into the clinic tonight with complaints of pain with taking a deep breath.  She had coughed up some blood once today and complained that it hurts when she takes a big breath in.  She is an athlete and remembered running in a race about three weeks ago and developed pain in the right calf and behind the right knee.  That pain has been improving over the last few weeks.  As you can probably guess by the title of this blog entry, she had a blood clot in her lungs.  Actually she had large blood clots called pulmonary emboli in both lungs.  She required transport emergently to the hospital for treatment. Definition:  A pulmonary embolism (PE) is a blockage of one of the blood vessels to the lungs.  These are usually caused by a blood clot that travels from somewhere else in the body, most commonly from the legs.  Other causes of blockages to the blood vessels in the lungs are air bubbles, or from tiny pieces of fat. A pulmonary embolism is a serious condition that is a medical emergency.  A blocked artery or vein in the lung can make it hard to breath and can lead to damage to the lungs and can even cause death. Most of the time the blood clots start in the legs, or in the pelvic area and then move along the veins and travel to the lungs. Symptoms:  People who have blood clots in the lungs might complain of: 1)   Sharp, stabbing pain when they take a breath in 2)   Coughing up blood 3)   Rapid heart rate 4)   Trouble breathing or feeling short of breath If you have any of these symptoms, it is important to call 9-1-1 and be evaluated in the hospital.  Do not try to drive yourself to the urgent care or to the hospital yourself. Risk Factors:  There are some factors that can increase the chance of having a blood clot in your lungs including: 1)   Having a family history of blood clots or blood clotting disorders 2)   Having recent surgery – especially on the knees, lower legs or pelvis 3)   Smoking 4)   Taking birth control pills or estrogen replacement 5)   Having a previous history of DVT (Deep Venous Thrombosis) or PE 6)   Having a history of heart failure 7)   Patients with cancer 8)   History of kidney problems such as nephrotic syndrome 9)   Having a recent trauma or injury with a large clot (hematoma) – more likely to cause DVT if it’s in the legs Diagnosis:  To diagnose a pulmonary embolism, special tests such as a special x-ray called a CT scan (Cat-Scan) with contrast.  During this test, the patient has special a detailed x-ray of the lungs while contrast (a solution of medication that can be seen under x-ray) is put into a vein (usually in the arm) and circulates through the lungs and rest of the body.  The CT scan is used to see the blood vessels and determine if a blood clot is present.  There are other tests to determine if a pulmonary embolism is present as well such as a ventilation/perfusion lung scan, but we usually use CT scan instead because it is easier and less time consuming.  If we suspect that there might be a blood clot in a patient’s leg, we can perform a vascular ultrasound to look for blood clots in the vessels of the legs. Treatment:  We start treatment of a pulmonary embolism without delay to prevent a new blood clot from forming and to reduce the chance of enlargement of the existing clot.  Usually your own body’s enzymes dissolve the clot.  We treat patients by anticoagulation.  That means that we give medications to reduce the body’s abilities to form new blood clots – this is also sometimes called using “blood thinners.”  It isn’t actually thinning the blood however.  For patients who are at high risk for forming new blood clots, we sometimes put small screens or “filters” in a major blood vessel such as the inferior vena cava to prevent a new blood clot from reaching the lungs. Most of the time we use a combination of oral anticoagulation medications such as Coumdin and also use an injectable medication such as heparin.  Patients who have pulmonary embolisms often stay in the hospital for a few days and receive intravenous heparin to prevent more blood clots from forming.  It takes a few days for the medication that is taken orally to become effective, so during this time the patient is giving the heparin either through an IV or the heparin is injected under the patients skin. Patients who have had a PE usually take the Coumadin (also called Warfarin) for a minimum of three months.  Some doctors recommend that patients with a PE take Coumadin or something similar for the rest of their lives.  Other medications to prevent blood clots might be used if the patient is pregnant or cannot tolerate Coumadin. Prevention:  Patients who are in the hospital and confined to the bed for extended periods of time are usually started on a prophylactic dose of heparin each day or special compression devices on their legs to prevent blood clots.  People who are on long air plane flights, car, bus or train rides should get up regularly and stretch their legs to help prevent the development of the blood clot in their legs (DVT).  Patients who have had recent surgery often use heparin injections even at home for a few days to help prevent the development of a blood clot in their leg. If you or someone you know if having symptoms of a pulmonary embolism (PE), they should dial 9-1-1 and go to the hospital immediately.  They should not attempt to drive to the hospital or urgent care.   I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, D.O.
Board Certified in Obesity Medicine and Family Medicine

This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.